Determination of the Monoclonal Antibody Tocilizumab by a Validated Micellar Electrokinetic Chromatography Method.

Tocilizumab is a monoclonal antibody used in the treatment of several inflammatory and autoimmune diseases as well as cancers. Tocilizumab improves clinical outcomes and reduce mortality rates in patients with COVID-19 disease. A novel, simple and reliable method was developed to determine tocilizumab using micellar electrokinetic chromatography (MEKC). Separation of tocilizumab and the internal standard, methotrexate, was achieved with a background electrolyte consisting of phosphoric acid buffer and sodium dodecyl sulfate (SDS) with UV detection at 195 nm. The method was linear in the concentration range from 10 to 250 µg/mL with correlation coefficient greater than 0.995. The method was successfully applied to the analysis of human and rat plasma samples with good recoveries. Sample preparation involved protein precipitation followed by dilution of the supernatant. The intra- and inter-day precisions were less than 5%, the accuracy varied from - 2.71 to 3.84%. The proposed method has acceptable analytical performance and could be applied in future clinical and pharmacokinetic studies including anticancer therapy. Supplementary Information: The online version contains supplementary material available at 10.1007/s10337-022-04148-w.